There is currently little to no understanding about type or frequency of patient safety issues in dentistry. Although dentists, like physicians, routinely perform highly technical procedures in complex environments, work in teams, and use a multitude of devices and tools, the patient safety revolution has bypassed dentistry. Only the grossest of dental care adverse events have been documented. In order to reduce patient harm, and improve the quality of care delivered, there is a critical need to define and identify adverse events in dental settings. As a long term goal, it is important to understand the causes of dental adverse events and develop interventions to minimize their occurrence. The objective of this application is to develop the tools necessary to document dental adverse events, generate a classification scheme and repository that can help organize and link adverse events, and allow 5 dental organizations to begin to systematically collect and analyze adverse events. Evidence about patient safety practices and adverse events is sorely lacking in dentistry. This proposal will take dentistry from a state of adverse event ignorance to achieving the first element of a Patient Safety Initiative: determining threats to dental patient safety. Developing the tools necessary to capture adverse events in dentistry and building a classification scheme to organize them are entirely novel contributions to dental care and research. This will enable a new field of dental research that has broad and direct implications on patient safety, quality improvement, and health economics. A Patient Safety Toolkit (PST) will be developed and validated for the documentation of adverse events in the dental setting. This toolkit will consist of 1) a chart review tool, (2) a novel severity ranking of dental adverse events, and (3) a novel, dental adverse events classification scheme. Next, a data repository will be build, allowing for the analysis of adverse events. Lastly, the PST will be deployed to the 5 participating dental institutions and each site will submit the results of their PST analyses to the data repository. This work will result in the first dental patient safety repository and reporting system, as well a the first empirical measurements of the occurrence of adverse events in the dental setting. Over 100,000 patients are seen in one year by the five sites, thus creating a rich set of data to improve the quality of dental care. Additionally, this project will greatly raise awareness of the importance of patient safety in dentistry.